arrays.yap

Go to the documentation of this file.

/*************************************************************************
*                                    *
*    YAP Prolog                              *
*                                    *
*   Yap Prolog was developed at NCCUP - Universidade do Porto    *
*                                    *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997   *
*                                    *
**************************************************************************
*                                    *
* File:     arrays.yap                       *
* Last rev:                              *
* mods:                                  *
* comments: Array Manipulation                   *
*                                    *
*************************************************************************/
 
%% @file pl/arrays.yap
 
%% @brief Prolog support for old arrays code
 
/**
   @addtogroup YAPArrays
   @{
 
*/
%
% These are the array built-in predicates. They will only work if
% YAP_ARRAYS is defined in Yap.h
%
 
/** @pred  array( +Name, +Size )
 
 
Creates a new dynamic array. The array is allocated in the global stack (or heap). Elements can be any term.xs
 
The  _Size_ must evaluate to an
integer. The  _Name_ may be either an atom (named array) or an
unbound variable (anonymous array).
 
Dynamic arrays are just a way to refer compound terms. Hence, space for
the array is recovered automatically on backtracking.
 
 
*/
array(Obj, Size) :-
    '$create_array'(Obj, Size).
 
 
% arithmetical optimization
'$c_arrays'((P:-Q),(NP:-QF)) :- '$c_arrays',
    '$c_arrays_body'(Q, QI),
    '$c_arrays_head'(P, NP, QI, QF).
'$c_arrays'(P, NP) :-
    '$c_arrays_fact'(P, NP).
 
'$c_arrays_body'(P, P) :-
    var(P), var.
'$c_arrays_body'((P0,Q0), (P,Q)) :- '$c_arrays_body',
    '$c_arrays_body'(P0, P),
    '$c_arrays_body'(Q0, Q).
'$c_arrays_body'((P0;Q0), (P;Q)) :- '$c_arrays_body',
    '$c_arrays_body'(P0, P),
    '$c_arrays_body'(Q0, Q).
'$c_arrays_body'((P0->Q0), (P->Q)) :- '$c_arrays_body',
    '$c_arrays_body'(P0, P),
    '$c_arrays_body'(Q0, Q).
'$c_arrays_body'(P, NP) :- '$c_arrays_lit'(P, NP).
 
%
% replace references to arrays to references to built-ins.
%
'$c_arrays_lit'(G, GL) :-
    '$array_references'(G, NG, VL),
    '$add_array_entries'(VL, NG, GL).
 
'$c_arrays_head'(G, NG, B, NB) :-
    '$array_references'(G, NG, VL),
    '$add_array_entries'(VL, B, NB).
 
'$c_arrays_fact'(G, NG) :-
    '$array_references'(G, IG, VL),
    (VL = [] -> NG = G;
        NG = (IG :- NB), '$add_array_entries'(VL, true, NB)).
 
'$add_array_entries'([], NG, NG).
'$add_array_entries'([Head|Tail], G, (Head, NG)) :-
    '$add_array_entries'(Tail, G, NG).
 
 
/** @pred  static_array_properties(? _Name_, ? _Size_, ? _Type_)
 
 
Show the properties size and type of a static array with name
 _Name_. Can also be used to enumerate all current
static arrays.
 
This built-in will silently fail if the there is no static array with
that name.
 
 
*/
static_array_properties(Name, Size, Type) :-
    atom(Name), atom,
    '$static_array_properties'(Name, Size, Type).
static_array_properties(Name, Size, Type) :-
    var(Name), var,
    current_atom(Name),
    '$static_array_properties'(Name, Size, Type).
static_array_properties(Name, Size, Type) :-
    '$do_error'(type_error(atom,Name),static_array_properties(Name,Size,Type)).
 
%% @}